The quantum Heisenberg antiferromagnet on the square lattice

The pure-quantum self-consistent harmonic approximation, a semiclassical method based on the path-integral formulation of quantum statistical mechanics, is applied to the study of the thermodynamic behaviour of the quantum Heisenberg antiferromagnet on the square lattice (QHAF). Results for various properties are obtained for different values of the spin and successfully compared with experimental data.Comment: Proceedings of the Conference "Path Integrals from peV to TeV - 50 Years from Feynman's paper" (Florence, August 1998) -- 2 pages, ReVTeX, 2 figure

On binary reflected Gray codes and functions

AbstractThe binary reflected Gray code function b is defined as follows: If m is a nonnegative integer, then b(m) is the integer obtained when initial zeros are omitted from the binary reflected Gray code of m.This paper examines this Gray code function and its inverse and gives simple algorithms to generate both. It also simplifies Conder's result that the jth letter of the kth word of the binary reflected Gray code of length n is 2n-2n-j-1⌊2n-2n-j-1-k/2⌋mod2by replacing the binomial coefficient by k-12n-j+1+12

Reentrant behavior of the phase stiffness in Josephson junction arrays

The phase diagram of a 2D Josephson junction array with large substrate resistance, described by a quantum XY model, is studied by means of Fourier path-integral Monte Carlo. A genuine Berezinskii-Kosterlitz-Thouless transition is found up to a threshold value g* of the quantum coupling, beyond which no phase coherence is established. Slightly below g* the phase stiffness shows a reentrant behavior with temperature, in connection with a low-temperature disappearance of the superconducting phase, driven by strong nonlinear quantum fluctuations.Comment: 4 pages, 7 figures, to appear in Phys.Rev.Let

Image Gallery: Super‐high magnification dermoscopy can identify pigmented cells: correlation with reflectance confocal microscopy

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Syphilis with HIV in Florence, 2003-2009: a 7-year epidemiological study.

SUMMARYThe aims of this study were to describe the trend of acquired syphilis in the city of Florence and its province over a 7-year period, to investigate sexual behaviours in the syphilis-infected population and to analyse syphilis/HIV co-infection. A total of 259 patients were classified according to age, sex and HIV infection. We estimated that from 2004 to 2008 cases increased by 248%. Most patients with concurrent HIV infection were male (31–45 years), but 40- to 60-year-old men who had sex with men predominated in both male and HIV-positive patients. Oral sex was identified as the most significant route of transmission, although most patients did not consider it so. Late-presenters with HIV accounted for 33% of HIV-positive patients: they were unaware of their HIV status and showed syphilis lesions only. In these cases, syphilis heralded the presence of HIV infection and allowed earlier diagnosis

Fenología, producción y conservación post cosecha de diferentes cultivares de cebolla en el sudeste de Buenos Aires

p.73-80Los cultivos de cebolla en el S.E. de la Provincia de Buenos Aires se realizan casi exclusivamente con el cultivar Valcatorce INTA. Aunque se ha propuesto el cultivo de cebollas de ciclo más corto, prácticamente no existe información acerca del comportamiento de estos cultivares en la región. En este trabajo se evalúa la fenología, producción y comportamiento postcosecha de seis cultivares de diferente longitud de ciclo, en comparación con Valcatorce. De acuerdo a nuestros ensayos, el empleo de los genotipos de ciclo corto evaluados sólo sería factible para consumo inmediato, debido a su mala conservación. Por otra parte, Valcatorce presentó la mejor conservación y una producción aceptable, mientras que Armada se destacó como una interesante alternativa. Se evalúan, asimismo, diferentes parámetros como indicadores de la longevidad post-cosecha

An Updated Algorithm Integrated With Patient Data for the Differentiation of Atypical Nevi From Early Melanomas: the idScore 2021

Introduction: It is well known that multiple patient-related risk factors contribute to the development of cutaneous melanoma, including demographic, phenotypic and anamnestic factors. Objectives: We aimed to investigate which MM risk factors were relevant to be incorporated in a risk scoring-classifier based clinico-dermoscopic algorithm. Methods: This retrospective study was performed on a monocentric dataset of 374 atypical melanocytic skin lesions sharing equivocal dermoscopic features, excised in the suspicion of malignancy. Dermoscopic standardized images of 258 atypical nevi (aN) and 116 early melanomas (eMM) were collected along with objective lesional data (i.e., maximum diameter, specific body site and body area) and 7 dermoscopic data. All cases were combined with a series of 10 MM risk factors, including demographic (2), phenotypic (5) and anamnestic (3) ones. Results: The proposed iDScore 2021 algorithm is composed by 9 variables (age, skin phototype I/II, personal/familiar history of MM, maximum diameter, location on the lower extremities (thighs/legs/ ankles/back of the feet) and 4 dermoscopic features (irregular dots and globules, irregular streaks, blue gray peppering, blue white veil). The algorithm assigned to each lesion a score from 0 to 18, reached an area under the ROC curve of 92% and, with a score threshold ≥ 6, a sensitivity (SE) of 98.2% and a specificity (SP) of 50.4%, surpassing the experts in SE (+13%) and SP (+9%).Conclusions: An integrated checklist combining multiple anamnestic data with selected relevant dermoscopic features can be useful in the differential diagnosis and management of eMM and aN exhibiting with equivocal features

Line-field confocal optical coherence tomography: a new tool for non-invasive differential diagnosis of pustular skin disorders

Background The spectrum of pustular skin disorders (PSD) is large and particularly challenging, including inflammatory, infectious and amicrobial diseases. Moreover, although pustules represent the unifying clinical feature, they can be absent or not fully developed in the early stage of the disease. The line-field confocal optical coherence tomography (LC-OCT) is a recently developed imaging technique able to perform a non-invasive, in vivo, examination of the epidermis and upper dermis, reaching very high image resolution and virtual histology. Objectives We aimed to investigate the potentialities of LC-OCT in the non-invasive differential diagnosis of a series of 11 PSD with different aetiology, microscopic features, body location and incidence rates. Materials and Methods Complete LC-OCT imaging (i.e. 2D/3D frames, videos) was performed on a total of 19 patients (10 females and 9 males) aged between 35 and 79 years. Images were blindly evaluated and compared with corresponding histopathologic findings. Results The LC-OCT imaging was able to detect with high accuracy the pustule structure including shape, margins, morphology and cellular content, along with peculiar epidermal and adnexal alterations in each condition, including: Acute Generalized Exanthematous Pustulosis, Generalized pustular psoriasis, Generalized pustular figurate erythema, Subcorneal Pustular Dermatosis, Intraepidermal IgA pustulosis, Palmoplantar pustulosis, Palmoplantar pustular psoriasis. Herpetic whitlow, Acrodermatitis continua of Hallopeau, Vesicopustular Sweet syndrome and Vesicopustular Eosinophilic cellulitis, with pustular appearance, were also compared. Conclusions The new LC-OCT can represent a rapid, non-invasive and painless tool which can help differentiating among PSD of different aetiology and microscopic morphology in clinical mimickers in daily practice

Decoherence times of universal two-qubit gates in the presence of broad-band noise

The controlled generation of entangled states of two quantum bits is a fundamental step toward the implementation of a quantum information processor. In nano-devices this operation is counteracted by the solid-state environment, characterized by a broadband and non-monotonic power spectrum, often 1/f at low frequencies. For single-qubit gates, incoherent processes due to fluctuations acting on different time scales result in peculiar short- and long-time behavior. Markovian noise gives rise to exponential decay with relaxation and decoherence times, T1 and T2, simply related to the symmetry of the qubit-environment coupling Hamiltonian. Noise with the 1/f power spectrum at low frequencies is instead responsible for defocusing processes and algebraic short-time behavior. In this paper, we identify the relevant decoherence times of an entangling operation due to the different decoherence channels originating from solid-state noise. Entanglement is quantified by concurrence, which we evaluate in an analytic form employing a multi-stage approach. The 'optimal' operating conditions of reduced sensitivity to noise sources are identified. We apply this analysis to a superconducting \sqrt{i-SWAP} gate for experimental noise spectra.Comment: 35 pages, 11 figure